Passwords seem to have outgrown their usefulness in authentication. It has proven to be an unreliable way of authenticating identity due to various obvious reasons. People want to choose easy-to-guess passwords such as names of people that are of personal importance or personal favorites. Hard-to-guess passwords on the other hand, can be so hard that even its owners find them difficult to remember.

Users often have the tendency to choose the same password for all their transactions such that a single password compromise would potentially put at risk all the other. Hard-to-guess passwords almost always necessitate writing them down which likewise exposes the person to potential risks. Forgetting passwords would mean seeking the assistance of a help desk or security administrator which is not exactly a minor irritant when it happens too often.